1. Field of the Invention
The present invention relates generally to fluid transfer tubes and more specifically it relates to a flexible low permeability hose for providing an impermeable length of tube to transfer fluids that is flexible.
2. Description of the Related Art
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
Single layer hose and multi-layered hose (e.g. hydraulic hose) have been in use for years. The main purpose of multi-layered hose is typically to provide a flexible interior material (e.g. rubber) surrounded by a protective exterior material for abrasion resistance (e.g. multiple layers of woven wire and rubber).
Hoses are used to transport various types of fluids (e.g. liquid coolant, vaporized coolant, combination of liquid and vaporized coolant) from one location to another location. For example, in a spray cooling liquid thermal management system hose may be utilized to transport liquid coolant from and to a spray module or other devices within the spray cooling liquid thermal management system.
Single-phase liquid thermal management systems (e.g. liquid cold plates) and two-phase liquid thermal management systems (e.g. spray cooling, pool boiling, flow boiling, jet impingement cooling, falling-film cooling, parallel forced convection, curved channel cooling and capillary pumped loops) have been in use for years for thermally managing various types of heat producing devices. Spray cooling technology is being adopted today as the most efficient option for thermally managing electronic systems. U.S. Pat. No. 5,220,804 entitled High Heat Flux Evaporative Spray Cooling to Tilton et al. describes the earlier versions of spray technology, as it relates to cooling electronics. U.S. Pat. No. 6,108,201 entitled Fluid Control Apparatus and Method for Spray Cooling to Tilton et al. also describes the usage of spray technology to cool a printed circuit board.
The problem with conventional hose technology, particularly for liquid thermal management systems, is that the hose often times results in a percentage of the coolant (e.g. perfluorocarbon fluids) permeating through the hose resulting in a loss of the coolant. Another problem is that external air and moisture are able to permeate the coolant being transferred within the hose thereby contaminating the coolant. Hose networks comprised of a material that has low permeability (e.g. ethyl vinyl alcohol copolymer, a.k.a. EVOH) is usually relatively rigid, stiff and difficult to utilize when the hosing is implemented in thickness designed for typical system operating pressures (e.g. 20-100 psi) thereby making it impractical as a flexible hose.
Hence, there is a need for a hose that is flexible, resistant to various types of coolants, and impermeable to various types of coolants, gases and other substances.